1. Field of the Invention
The present invention relates to measuring the displacement of an object, and specifically to systems, program product, and methods to determine the displacement of objects at a long range.
2. Description of Related Art
Determining the displacement of objects can be accomplished by various approaches. One approach is to use a measuring device such as a ruler or micrometer to measure an object's displacement at close range. These measuring devices, however, may not provide the required accuracy. Generally, displacement sensors can also be utilized to measure the displacement of an object. U.S. Pat. No. 7,151,568 describes a displacement sensor that uses a standard imaging unit such as a digital camera to capture images of an object that are then processed to measure the object's displacement. These displacement sensors can be costly. Further, such cameras are limited to focusing on the movement of an object within the field of view that is less than one inch. Accurate and precise displacement measurement of objects in hazardous or inaccessible locations, even with humans wearing protective clothing, are impossible or impractical under these approaches and can be costly, dangerous, or inaccurate. Cameras have also been used to track movement in a valve component as shown, for example, in U.S. Pat. No. 5,056,046 and to acquire data from bar codes affixed to containers as shown, for example, in U.S. Pat. No. 6,626,361. Further, laser range finders can be used to measure displacement. Such devices, however, only measure distance parallel (depth) to the line of sight. Further, laser recoil off the target object can provide inaccurate measurements.
Recognized by the inventor is that the ability to measure displacement of objects such as machinery, valves, and containers that is perpendicular to the line of sight without contacting them is valuable, for example, because the objects can then be moved or returned to a desired position based on that measurement. This is especially valuable where the displacement can be relatively large but nevertheless must be known with micron accuracy, and where the objects of interest are located in radioactive, chemically reactive, high voltage, or other hazardous locations, and thus are not accessible for displacement measurement by personnel. Of further value is the ability of a system to determine displacement measurements where the movement of the object in the field of view ranges from a fraction of an inch to approximately 2 inches or more.
A need, therefore, exists for a system, program product, and computer implemented method to perform algorithms that can accurately determine the displacement, with micron accuracy, of objects located in a hazardous or inaccessible location and at a long range from an optical viewing device.